A review of the use of genetically engineered enzymes in electrochemical biosensors.
ABSTRACT This article gives an overview of the electrochemical biosensors that incorporate genetically modified enzymes. Firstly, the improvements on the sensitivity and selectivity of biosensors that integrate mutated enzymes are summarised. Next, new trends focused on the oriented immobilisation of mutated enzymes through specific functional groups located at their surface are reviewed. Finally, the effect of enzyme mutations on the electron transfer distance and kinetics of electrochemical biosensors is described.
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ABSTRACT: This work presents an application of automatic flow based biosensor to detect binary (chlorpyriphos-oxon (CPO) and malaoxon (MO)) organophosphate (OP) mixtures in milk, based on artificial neural network (ANN). Genetically modified acetylcholinesterase (AChE) B394 and B4 were used as a biological recognition element for sensor development. AChE binds with OPs irreversibly, creating an anionic phosphonyl species. The enzymes were coupled on screen printed electrodes (SPEs) and inserted in a flow cell connected to the potentiostat and syringe pump. In order to model the combined response of CPO and MO, a total set of 19 mixtures were prepared using ANN. The modeling was validated with an external test of 6 milk samples spiked with CPO and MO mixtures. The spiked concentrations of CPO and MO were ranged from 5 × 10−10 to 5 × 10−12 M and 1.01 × 10−10 to 9.17 × 10−11 M, respectively. These concentrations were determined using factorial designing (FD) method and the obtained and expected recovery values in milk showed good co-relation. The average % recovery yields for CPO and MO are 109.53 and 100.66, respectively.Sensors and Actuators B Chemical 03/2015; 208. DOI:10.1016/j.snb.2014.11.011 · 3.84 Impact Factor
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ABSTRACT: The extensive use of carbamate pesticides in modern agriculture has raised serious public concern regarding the environment and food safety. Due to their broad spectrum of biological activity, carbamates can be used as insecticides, fungicides, nematocides, acaracides, molluscicides sprout inhibitors or herbicides. Contamination of fruits and vegetables may result from treatment as well as from conditions such as improper use of pesticides, residues from preceding treatments in the soil and cross-contamination. Sources of residues in products of animal origin include contaminated water or feed, pesticide-treated housing, and contaminated milk. The presence of pesticide residues is a concern for consumers because carbamates are known to have potential harmful effects to other non-targeted organisms than pests and diseases. The major concerns are their toxic effects such as interfering with the reproductive systems and foetal development. In this chapter, the more relevant contributions, of the last ten years, to the current knowledge on several aspects regarding carbamate pesticides, such as mode of action, effects on human health, legislation, monitoring, human exposure to carbamate residues, risk and exposure assessment will be discussed.The Impact of Pesticides, 1 edited by Milan Jokanović, 01/2012: chapter Carbamates: Human Exposure and Health Effects: pages 21-38; AcademyPublish.org., ISBN: 978-0-9835850-9-1
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ABSTRACT: This work presents a hardware implementation of artiﬁcial neural networks (ANNs) using a dsPIC microcontroller to resolve mixtures of pesticides measured by amperometric acetylcholinesterase (AChE) biosensors. The response of three biosensors with different concentrations of Chlorpyrifos Oxon (CPO) and Chlorfenvinfos (CFV) was modeled by two ANNs, which were implemented on the dsPIC . The performance of the ANNs was good, the prediction ability was better than 0.986 when the obtained values were compared with those expected for a set of eight external test samples, which were not used for training. This implementation is proposed to develop low-cost analytical chemical specialized tools.Computers and Electronics in Agriculture 08/2010; 74(2). DOI:10.1016/j.compag.2010.08.003 · 1.49 Impact Factor